Apparatus for modifying blood

Abstract

The invention relates to an apparatus for modifying blood, the apparatus comprising a housing, which has an inlet and an outlet and delimits a housing volume in which a binding agent is located which at least partially comes into contact with the blood when the blood is flowing through the housing. The invention is characterised in that the binding agent comprises a carrier substrate, to which a material is applied which has a surface that is freely accessible inside the housing volume and has a chemical binding property of the spin trap type.

Description

[0001] Device for modifying blood

[0002] Technical area

[0003] The invention relates to a device for modifying blood, comprising a housing having an inlet and an outlet and defining a housing volume in which a binding agent is arranged which comes into at least partial contact with the blood as it flows through the housing.

[0004] Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are constantly present in aerobic organisms and have important physiological functions. However, overproduction also contributes to various diseases as "oxidative stress." Under normal physiological conditions, a balance exists between "oxidative" and "antioxidative" processes. A shift in this balance toward a predominance of ROS or RNS formation is referred to as "oxidative stress."

[0005] ROS and RNS can carry out or trigger a variety of chemical reactions that can lead to irreversible damage to cellular structures and functional units, such as lipid membranes, DNA and proteins, and thus contribute significantly to cell aging.

[0006] Since an imbalance with predominance of ROS and / or RNS production in a complex organism, such as humans in particular, is to be avoided, it is desirable to maintain the redox balance between the oxidizing and reducing substances within an aerobic organism at all times.

[0007] Furthermore, studies have shown that human blood that comes into contact with technical surfaces, whether during a surgical procedure or through surface contact with components contained in an extracorporeal circuit, leads to increased formation of ROS and RNS, significantly increasing their concentration in the blood. After the blood flows back into the body from the extracorporeal circuit, the balance in favor of oxidants is disturbed, meaning the body experiences oxidative stress. Particularly in hemodialysis patients who are permanently dependent on dialysis, serious consequences arise, such as progressive vascular sclerosis and coronary heart disease, which significantly reduce quality of life and life expectancy.

[0008] State of the art

[0009] The document EP 1 423 518 B1 describes a diagnostic test method which makes it possible to determine the status of oxidative stress in an aerobic organism in order to select or determine therapeutic methods for reducing oxidative stress or to check their effectiveness.

[0010] In the article by Sergey I. Dikalov et al., Electron Paramagnetic Resonance Measurements of Reactive Oxygen Species by Cyclic Hydroxylamine Spin Probes, ANTIOXIDANTS & REDOX SIGNALING, Volume 28, Number 15, 2018, DOI: 10.1089 / ars.2017.7396, the use of cyclic hydroxylamine probes as effective scavengers of superoxide radicals is proposed, allowing quantitative measurements of superoxide radicals with high sensitivity both in vitro and ex vivo in cells and tissue samples.

[0011] The dissertation by Zarif Najafi Nooshin, Mohammad Hassan: "A Study of Mechanochemical Reactions of Spin Traps in Hydrocarbon Polymers, 1990, Dissertation, University of Aston Birmingham" deals with the improvement of the antioxidant properties of plastic compositions through chemical reactions of spin traps in hydroxyl polymers. The publication WO 2023 (178170 A2), published subsequently to this description, describes a precaution for preventing degradation damage to medical implants, particularly implanted sensors, to whose surface a polymer is applied to which binding molecules are bound for reaction with reactive oxygen species.

[0012] US 2011 / 0236989 A1 discloses analytical sensors with antioxidant protection to protect them from reactive oxygen. These are primarily so-called equilibrium fluorescence indicator systems, which are protected by an antioxidant polymer matrix that can capture reactive oxygen radicals.

[0013] The document DE 101 21 893 B4 describes a filter for removing heparin from blood in an extracorporeal blood circuit.

[0014] The document EP 3 530 302 A1 discloses a device for removing noxious substances from blood in general and focuses primarily on the mechanical structure of the device, which consists of a bundle of hollow fibers, the inner surfaces of which are provided with hemocompatible and anticoagulant coatings.

[0015] Description of the invention

[0016] The invention is based on the object of developing a device for modifying blood with a housing that has an inlet and an outlet and delimits a housing volume in which a binding agent is arranged, which comes into at least partial contact with the blood as it flows through the housing, in such a way that the proportion of ROS and / or RNA present in the blood is lower after contact with the binding agent than before contact. In particular, the device is intended to effect a modification of the blood in such a way that ROS and / or RNA contained in the blood are selectively inactivated in order to reduce or minimize the oxidative stress acting on the organism and thus the subsequent damage.

[0017] The solution to the problem underlying the invention is defined in claim 1. Advantageous features further developing the inventive concept can be found in the subclaims and the further description.

[0018] A device according to the invention for modifying blood, comprising a housing having an inlet and an outlet and defining a housing volume in which a binding agent is arranged, which at least partially comes into contact with the blood as it flows through the housing, is characterized in that the binding agent has a carrier substrate to which a material is applied, which has a surface freely accessible within the housing volume and which has a chemical binding property in the manner of a spin trap.

[0019] The underlying concept of the device is based on the fact that ROS and RNS are chemically reactive molecules that undergo relatively non-selective redox reactions. On the other hand, materials in the form of certain molecules are known that react selectively with ROS and RNS, subsequently chemically inactivating them. Such materials possess selective chemical binding properties similar to a spin trap and are used in conventional spin trapping methods. Typical materials or molecules possessing such selective binding properties include nitrones or nitroso compounds, which react rapidly and quantitatively with free, short-lived radicals X* to form a long-lived radical. During the chemical reaction, for example, a reactive ROS radical is bound to a double bond of a diamagnetic "spin trap," forming a much more stable radical.A possible reaction example of a nitrone compound (H-RI )=(ON-R2) with a free radical X* is shown below:.

[0020] Another reaction example is illustrated below:

[0021] In this case, the free radical (see middle compound) simply transfers an unpaired electron to the spin trap or absorbs it, depending on the redox potential. For example, if the free radical is a superoxide (O2-), then oxygen (O2) is formed upon oxidation, and water upon reduction. In both cases, the radical is inactivated, but it does not bind to the spin trap.

[0022] The device according to the invention essentially consists of a carrier substrate to whose surface a material is bonded via a covalent bond with the chemically selective binding properties described above. The covalent bond ensures that the at least one material possessing chemical bonding properties similar to a spin trap remains bonded to the carrier substrate both before and, in particular, after the chemical reaction with a free radical. This ensures that the free radical, which chemically reacts with the material and forms a solid material bond with it, is and remains extracted from the blood.

[0023] Suitable classes of substances for the formation of the carrier substrate are

[0024] Polymethyl acrylates, polyurethanes, aminocellulose derivatives, polyamides or

[0025] Polyurethanes, polyethylenes, polypropylenes, poly-4-methyl-1-pentenes, polyimides, polysulfones, and polymers of polysulfones. Particularly suitable classes of substances are those that are already certified for medical use and are used in medical products, such as aminocellulose derivatives, polysulfones, or polyurethanes.

[0026] The choice of shape and size of the carrier substrate depends on the housing shape and dimensions, as well as the volume enclosed by the housing, in which the carrier substrate is to be arranged. The housing is designed as a flow-through housing with an inlet and an outlet through which blood flows. The housing is preferably integrated into an extracorporeal blood circuit, preferably immediately before re-entry into the human body. In order to prevent, on the one hand, any significant flow pressure losses within the housing and, on the other hand, to ensure that the largest possible volume of blood can enter into chemical interaction with the at least one material bound to the carrier substrate surface, the carrier substrate surface must be maximized, i.e., made as large as possible, e.g., by folding or by providing porous surface structures or by designing the carrier substrate as a knitted fiber fabric, etc., so that flow over and / or through the support structure, including the at least one material covalently bonded thereto, is possible. Alternatively, the carrier substrate can be particulate and arranged within the housing in the form of free bulk material, so that the freely accessible surfaces of the material attached to the particles can be flushed by the blood as it flows through the housing. In this case, a retaining element for the particles is arranged upstream of the outlet in the flow direction.

[0027] As already mentioned, suitable materials are those that form a covalent bond with the surface of the carrier substrate and possess chemical bonding properties similar to a spin trap, preferably containing at least nitrones and / or nitrous compounds. A particularly preferred material that reacts quickly and effectively with ROS and RNS is CMH, 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine. Thus, one CMH molecule is capable of inactivating one ROS molecule. Furthermore, the two redox states of the CMH molecules are distinguished by their color appearance. The starting CMH molecule is colorless and, after reacting with the ROS molecule, becomes colored. This color change can be used to determine the "consumption level" of the CMH molecules stored on the carrier substrate. This can be determined either visually by a person or automatically using an optical sensor mounted in or on the housing.

[0028] Other suitable materials with chemical binding properties in the form of a spin trap are mentioned below:

[0029] BMPO, C10H17NO3, (or BocMPO), 5-tert-butoxycarbonyl-5-methyl-1 - pyrroline-N-oxide,

[0030] CYPMPO, 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide,

[0031] DEPMPO-biotin, C24H42N5O8PS, [(3S)-2-diethoxyphosphoryl-2-methyl-1 -oxido- 3,4-dihydropyrrol-1 -ium-3-yl]methyl N-[3-[5-[(3aR,4R,6aS)-2-oxo- 1 ,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]propyl]carbamate,

[0032] EMPO, C8H13NO3, 2-Ethoxycarbonyl-2-methyl-3,4-dihydro-2 / - / -pyrrole-1 -oxide Nitrosobenzene, CeHsNO,

[0033] POBN , C10H14N2O2, a-(4-Pyridyl 1 -oxide)-N-fe / Y-butylnitrone

[0034] PTIO, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, is a specific scavenger of NO TEMPO, 2,2,6,6-tetramethylpiperidin-1-oxyl hydroxylamine, trityl radicals, ebselenic acid, organic dithio acid. In a preferred embodiment of the device, at least one of the above compounds, each with different chemical binding properties for free radicals, is covalently bonded to the surface of the support structure. The at least two compounds react by copolymerization to form a copolymer that is covalently bonded to the surface of the support structure. For example, a mixture of different nitrone or nitroso compounds can be produced in this way.

[0035] ROS and RNS can react with the different nitrone or nitroso compounds contained in the copolymer at different reaction rates, so that depending on the selected ratio and type of compounds contained in the copolymer, such as hydroxylamines and trityl radicals, a desired final concentration of free radicals in the blood can be achieved.

[0036] The device according to the invention can be used as an integral component in extracorporeal circulation along any blood-containing or non-blood-containing line. The extracorporeal circulation can be implemented in the form of a fluid circuit of the following type: extracorporeal membrane oxygenation for lung support (ECMO), extracorporeal support of the heart and lungs (ECLS, AV-ECMO), heart-lung machine for cardiac surgery, mechanical circulatory support systems, both ventricular assist devices (LVAD) and artificial hearts (TAH), blood purification circuit (dialysis), lipid filtration (lipid apheresis).

[0037] The blood-containing or non-blood-containing lines are preferably lines of the following type: collection systems for blood donations, blood collection (bloodletting) for polycythemia, administration of blood or blood components (erythrocyte concentrates, plasma, FFP, etc.), or priming solutions for extracorporeal circulation. Brief description of the invention

[0038] The invention is described below, without limiting the general inventive concept, using exemplary embodiments with reference to the drawings. They show:

[0039] Fig. 1 Representation of an extracorporeal circulation with the device according to the solution,

[0040] Fig. 2a, b alternative embodiments of the device according to the solution and

[0041] Fig. 3a, b Diagrams illustrating the effect of reducing ROS from blood.

[0042] Ways of implementing the invention, industrial applicability

[0043] Figure 1 shows a schematic of an extracorporeal blood circuit, with a line 2 leading away from a person 1, along which a therapy and / or heart-lung support unit 3 is installed, for example in the form of a membrane oxygenator, dialysis machine, lipid filtration unit or a heart-lung machine, etc. In the direction of flow after the therapy and / or heart-lung support unit 3 there is a line 4 leading back into the patient 1, along which the device 5 according to the solution is installed immediately before entering the patient 1 and modifies the patient's blood in such a way that the proportion of free radicals contained in the blood is reduced. The reduction of the free radicals contained in the blood, in particular ROS and RNS, occurs through selective removal orExtraction from the blood by chemical binding of the free radicals to at least one material provided within the device 5 which has chemical binding properties in the manner of a spin trap.

[0044] In this context, it should be noted that any surgical intervention, as well as any use of technical medical components that come into contact with blood, places both physical strain on the blood and biochemical or oxidative stress on it, leading to an increase in ROS / RNS in the blood. This also applies in principle to the device 5 according to the solution, whose biochemical effect on reducing free radicals in the blood, however, far outweighs any resulting formation or release of free radicals. This is also the reason why the device 5 according to the solution is to be placed in an extracorporeal blood circuit outlined in Figure 1 immediately before re-entry into the patient 1, in order to minimize the "artificial" extracorporeal blood flow path to the patient, along which free radicals can also form.

[0045] Fig. 2a shows an embodiment of a device 5 according to the invention with a housing 8 having an inlet 6 and an outlet 7, which defines a housing volume 9 in which a carrier substrate 10 is arranged, to the surface of which a material 11 is covalently bonded, which in the case shown is a copolymer of two compounds 12, 13. The compounds 12, 13, for example, CMH and TEMPO or hydroxylamine and triphenylmethyl radicals, are capable of binding the free radicals with different selectivity and reaction rates. Of course, copolymer materials 11 comprising more than two compounds, as mentioned above, are also conceivable and advantageous.

[0046] When blood flows into the housing 8 via the inlet 6, it comes into contact with the material 11 covalently bound to the carrier substrate 10, to which the free radicals ROS / RNS contained in the blood bind. Accordingly, blood flows out of the housing 8 via the outlet 7 with a controlled reduction in the proportion of free radicals.

[0047] The carrier substrate 10 should be designed with as large a surface area as possible, so that the largest possible proportion of blood, preferably the entire volume of blood flowing through the housing 8, can chemically interact with the material 11. It is therefore advisable to fold the flat carrier substrate 10 and / or structure its surface to increase the surface area. Instead of flat carrier substrates 10, fibrous carrier substrates 10, preferably converted into a knitted fabric, are also conceivable, to whose surface the material (11) can covalently bond.

[0048] When using a material 11 whose redox states differ in color, as is the case with CMH molecules, for example, an optical sensor 16 additionally mounted in or on the housing 8 can determine the proportion of CMH molecules that have already reacted with a free radical. In this way, a "consumption state" of the device 5 can be automatically detected.

[0049] Figure 2b shows an alternative embodiment of the device 5 with a housing 8 containing a particulate carrier substrate 10 in the form of bulk material. Each individual carrier substrate particle 14 (see detailed illustration) has covalently bonded material 11 on its surface, in the form of a copolymer composed of at least one compound 12, 13.

[0050] In order to prevent the particulate carrier substrate 10 from escaping uncontrollably through the outlet 7 of the housing 8, a retaining element 15 in the form of a sieve or the like is arranged within the housing 8 immediately in front of the outlet 7.

[0051] Blood-permeable membrane structures are also conceivable as a carrier substrate. These structures are arranged within the housing 8 so that blood flows through them. The membrane pores of the membrane structures are dimensioned such that they can be penetrated by blood components without causing damage, while at the same time ensuring biochemical interaction with the material attached to the membrane pore surface, whose material surface possesses chemical bonding properties similar to a spin trap.

[0052] For support substrates designed as membranes, polysulfones or polymers from the polysulfone family, e.g., polyethersulfones / polyarylethersulfones, are preferred. These can be easily functionalized with spin traps. Polyethylene (PE), polypropylene (PP), poly-4-methyl-1-pentene (PMP), and polyimide (PI) are also suitable as membrane materials, especially in conjunction with an ECMO.

[0053] In two experiments, the positive effect of efficient ROS reduction was demonstrated both in an aqueous solution and in blood plasma.

[0054] Figure 3 A shows a diagram from which the measured amount of ROS can be determined based on the electron spin resonance intensity (see ordinate) as a function of the magnetic excitation field strength (see abscissa).

[0055] The starting point is an aqueous solution containing a flavin mononucleotide-containing protein, in which superoxides are formed upon oxygenation and light exposure. This ensures that, depending on the duration of light exposure, e.g., 6 minutes, a defined amount of superoxide is produced in a short time. The ROS concentration is then determined using a spin trap; see the upper spectrum in Fig. 3 A, which shows several intensity peaks indicating an increased ROS concentration.

[0056] Subsequently, a test polymer, poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA), whose surface had been copolymerized with a nitroxide spin trap, was added to the aqueous solution as a carrier substrate. After an incubation time of 15 minutes, the middle spectrum in Figure 3a was measured, which showed only two distinct peaks. Finally, the EPR spectrum was determined after separation of the PTMA copolymerized with the spin trap from the aqueous solution; this spectrum corresponds to the lower spectrum in Figure 3A. It is clearly visible that no EPR signal is visible in the filtrate, meaning that no ROS are detectable in the aqueous solution. Figure 3B shows a diagram-based comparison of two ROS concentration measurements in a blood plasma.

[0057] The starting point is a human blood sample from which blood plasma was extracted, the ROS concentration of which was determined using a spin trap and is given as 1.31 pM.

[0058] Subsequently, a test polymer, poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA), is added to the blood plasma as a carrier substrate. The surface of the polymer has been copolymerized with a nitroxide spin trap. After a 15-minute incubation period, the spin trap measured an ROS concentration of 0.87 pM. This value could be further reduced by completely extracting the test polymer from the blood plasma.

[0059] List of reference symbols

[0060] person

[0061] efferent line

[0062] Therapy and / or cardiopulmonary support unit

[0063] Return line

[0064] Solution-related device

[0065] inlet

[0066] Outlet

[0067] Housing

[0068] Housing volume

[0069] Carrier substrate

[0070] material

[0071] Substance group I with iron binding properties of a spin trap

[0072] Substance group II with iron binding properties of a spin trap

[0073] Carrier substrate particles

[0074] Retaining element

[0075] Optical sensor

Claims

Patent claims 1. Device for modifying blood with a housing (8) which has an inlet (6) and an outlet (7) and delimits a housing volume (9) in which a binding agent is arranged which comes into at least partial contact with the blood as it flows through the housing (8), characterized in that the binding agent has a carrier substrate (10) to which a material (11) is applied which has a surface which is freely accessible within the housing volume (9) and which has a chemical binding property in the manner of a spin trap.

2. Device according to claim 1, characterized in that the one material (11) is covalently bonded to the carrier substrate (10).

3. Device according to claim 1 or 2, characterized in that the carrier substrate (10) consists of one of the following classes of substances: polymethyl acrylate, polyurethanes, aminocellulose derivatives, polyamides, polyurethanes, polyethylene, polypropylene, poly-4-methyl-1-pentenes, polyimides, polysulfones, polymers of polysulfones.

4. Device according to one of claims 1 to 3, characterized in that the material (11) comprises at least one nitrone and / or nitrose compound.

5. Device according to claim 4, characterized in that a free radical X* dissolved in the blood reacts with the material (11) in the following chemical reaction:

6. Device according to claim 4, characterized in that a free radical dissolved in the blood in the form of reacts with the material (11 ) in the following chemical reaction:

7. Device according to one of claims 1 to 6, characterized in that the material (11) comprises at least one of the following material compounds: TEMPO, 2,2,6,6-Tetramethylpiperidine-1-oxyl 4-carboxy TEMPO, 4-carboxy-2,2,6,6-tetramethyl-piperidine-1-oxyl BMPO (BocMPO), C10H17NO3 CYPMPO, 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide, DEPMPO-biotin, C24H42N5O8PS, [(3S)-2-diethoxyphosphoryl-2-methyl-1 -oxido- 3,4-dihydropyrrol-1 -ium-3-yl]methyl N-[3-[5-[(3aR,4R,6aS)-2-oxo- 1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]propyl]carbamates EMPO, C8H13NO3 Nitrosobenzene, CeHsNO, POBN, C10H14N2O2POBN PTIO , 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl 3-oxide PROXYL, 2,5,5- Tetramethyl-pyrrolidine-1-oxyl Ebselenic acid organic dithio acids.

8. Device according to claim 7, characterized in that the material (11) has at least two of the substance compounds (12, 13) which are connected by means of a copolymerization.

9. Device according to one of claims 1 to 8, characterized in that the material (11) comprises hydroxylamines and / or triphenylmethyl radicals.

10. Device according to one of claims 1 to 9, characterized in that the carrier substrate (10) has pores and has a porous surface structure.

11. Device according to one of claims 1 to 10, characterized in that the carrier substrate (10) is arranged in a stationary manner within the housing (8) so that the freely accessible surface of the material (11) is oriented parallel to a blood flow forming within the housing (8).

12. Device according to one of claims 1 to 10, characterized in that the carrier substrate (10) is formed particulately and is arranged within the housing (8) in the form of free bulk material, so that the freely accessible surfaces of the material (11) attached to the particles (14) can be washed around by the blood as it flows through the housing (8).

13. Device according to claim 12, characterized in that a retaining element (15) for the particles (14) is arranged in front of the outlet (7) in the flow direction.

14. Device according to one of claims 1 to 13, characterized in that an optical sensor (16) is provided on or in the housing (8), which is designed to detect a color change on the freely accessible surface of the material (11).

15. Device according to one of claims 1 to 14 as an integral part of any extracorporeal circulation and any blood-containing and non-blood-containing lines.

16. Device according to claim 15, characterized in that the extracorporeal circulation is in the form of a fluid circuit of the following type: Extracorporeal membrane oxygenation for lung support (ECMO), extracorporeal support of heart and lungs (ECLS, AV-ECMO), heart-lung machine for cardiac surgery, Mechanical circulatory support systems, both ventricular assist devices (LVAD) and total artificial hearts (TAH), blood purification circuit (dialysis), lipid filtration (lipid apheresis).

17. Device according to claim 15, characterized in that any blood-containing and non-blood-containing lines are of the following type: Collection systems for blood donations, Blood sampling (bloodletting) in polycythemia, Administration of blood or blood components (erythrocyte concentrates, plasma, FFP), priming solutions from extracorporeal circulation.

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